Carbon dioxide removal or Carbon dioxide air capture is a form of carbon capture. It removes carbon dioxide from ambient air by carbon dioxide scrubbing. It is a different approach to removing CO2 from the stack emissions of large point sources, such as fossil fuel fired power stations. It is regarded as greenhouse gas remediation, which is a branch of geoengineering. Some commentators regard air capture as a form of carbon capture and storage, but CCS is usually used to describe capture at source rather than capture from ambient air. CDR methods are notably supported by IPCC chief Rajendra Pachauri.